Sen. Rob Portman's reversal on same-sex-marriage has cost him a few points in popularity, but he still appears to be in good shape among Ohio voters as he looks ahead to a re-election bid in 2016.

According to the latest Quinnipiac University poll, the Republican's approval rating has slipped to 40 percent since he declared his support for legalizing gay marriage.

That's a drop of four points, compared to a February poll that showed him with an approval rating of 44 percent among registered voters.

The overall dip in approval is "fueled mainly" by a six-point loss in support from Republican voters, according to the Quinnipiac poll of 1,138 registered voters taken April 10-15. GOP voter support of Portman dropped from 63 percent in February to 57 percent in the current survey.

The poll found that Portman's views on the issue of gay marriage were in line with most Ohioan's, who support same-sex marriage by a margin of 48 percent to 44 percent.

"Sen. Portman's reversal on same-sex marriage has cost him a little support in his Republican base, but has little impact among Democrats and independent voters,” said Peter Brown, assistant director of the Quinnipiac University Polling Institute. “The movement in his numbers has not been massive and the overall movement towards acceptance of same-sex marriage, which we see in Ohio and elsewhere, could help him in the long run, especially if he seeks reelection four years from now.”

The April poll also measured Ohioan's opinions on a number of other issues, including gun control and the president's performance.

On gun control, the survey found that 84 percent, including 80 percent of voters who are gun owners, support universal background checks on gun buyers. But 50 percent of those polled said they are concerned the government will use the information obtained through checks to confiscate firearms from legal owners.

At the same time, however, a 52 percent majority said they would be more likely to vote for a member of Congress who supports background checks than one who doesn't.

The Quinnipiac survey also found that President Barack Obama’s job performance rating continues to dip in Ohio, where it now stands at 45 percent approval to 51 percent disapproval. That's a represents a three point drop in approval from last month and a nine point drop since last December when 54 percent of Ohioans thought he was doing a good job.